The caption for the photo reads: 'This morning on the A40 just coming out of Abergwili a group of hunting dogs came running down from the forest on the hill onto the busy road with a fox and started tearing it to pieces.

'One of the dogs was hit and killed by a car in the process and it was one the most horrible things to experience. If anybody knows who these dogs belong to and whether or not there was a hunt organised for this morning please contact the police.'

The incident has caused fury among anti-hunt campaigners who say it is an example of illegal activity happening all over Britain.

One of the dogs was also reportedly hit by a car in the incident.

This is South Wales reports that witnesses said the chase came from the wooded area and onto the busy road.

It is unclear which hunt the dogs belong to. Carmarthenshire Hunt confirmed to police that it was 20 miles away from the incident in the Pendine area.

A Dyfed-Powys Police spokesman said: 'Dyfed-Powys are investigating an incident which happened on the A40 between Abergwili and Whitemill shortly after 10.30am Saturday.

'The incident involved a pack of hunting dogs and a fox. As part of the investigation officers have been speaking with witnesses and members of the hunt to establish what happened.

'These inquiries are ongoing and it would be inappropriate to comment further at this point.'

Regional Director of Countryside Alliance Rachel Evans told This is South Wales there are 'many registered and unregistered packs' of hunting dogs in the area.

The Hunting Act 2004 bans the hunting of wild mammals with dogs in England and Wales.